Questions tagged [cisco]

The major provider of networking equipment. This is a generic tag to be used when no more specific tags are available. See the list of tags in Help Center Tag page.

Filter by
Sorted by
Tagged with
4
votes
2answers
3k views

Connecting Layer 2 switchport to layer 3 port

I have a config that I am trying to bring up, and in my mind it should work, but perhaps I am missing something. The idea is that one end of the link is a layer 3 interface on a router. The other end ...
3
votes
1answer
89 views

Why can't get host's mac address on l2 switch through snmp? But can get it on l3 router

I am trying to get computer's mac address through snmp. I have an envirmont in GNS3: l3 R1's image is vios-adventerprisek9-m.SPA.157-3.M3 l2 SW1's image is viosl2-adventerprisek9-m.SSA....
4
votes
1answer
89 views

BGP | Advertise a summary prefix out to customer location

I don't know what I should be using for this or how I should go about it. In my lab where I am testing out the BGP configs that I've learned I want my ISP topology to have a summary prefix for the ...
1
vote
1answer
256 views

BGP Best Path Selection Algorithm

According to this cisco document (https://www.cisco.com/c/en/us/support/docs/ip/border-gateway-protocol-bgp/13753-25.html), shortest AS_PATH is the #4 algorithm in the sequence to evaluate, out of 13 ...
3
votes
2answers
251 views

EIGRP unequal load balancing, variance command

Is correct to say that the value inserted in the variance command, lets say the value of "2" on a route that has a cost of, lets say "100", will unequally load balance all routes up to a cost of 200 ? ...
1
vote
2answers
137 views

Static routing using 2 routers and 1 multi-layered switch

I'm trying to configure a static route between two routers and a layer 3 switch as follows - Router 0 interface FastEthernet0/0 ip address 172.17.10.1 255.255.255.252 duplex auto speed auto ! ...
0
votes
0answers
16 views

ASA ping outside to inside private ip's?

i am new asa and cisco as well , what i am trying to do to perform this lab , only 1 issue is there , i need help in it, i can ping from pc0 to router0 in other way I can ping inside to outside , but ...
1
vote
1answer
19 views

Where can one find how much memory is currently allocated to logbuffer?

Do you know where it can be checked, how much memory is currently being used by the logbuffer? some-switch#show log | i Buffer|Trap|udp Buffer logging: level debugging, 2268 messages logged, xml ...
2
votes
1answer
19 views

Trex not receiving any packets

This is my setup to benchmark my server Diagram Trex version v2.88 Trex server MAC ens2f0: f8:f2:1e:5c:bf:78 ens2f1: f8:f2:1e:5c:bf:79 DUT server MAC eth0: fa:16:3e:1c:be:82 eth1: fa:16:3e:d5:37:b1 ...
3
votes
3answers
3k views

How to enable DHCP Cisco router

This is what I have done in my GNS3 R3 - Router R4 - Switch I have installed GNS3 and trying to enable on Router as mentioned above depict. How to enabled DHCP on Cisco router R3 ?
0
votes
1answer
14 views

How to deny ICMP from 1 host on the server - Cisco Packet Tracer

How I can to setup the server firewall to deny any ICMP traffic come only from host 1 while permitting the other. host 1 is a switch Vlan = 192.168.10.2/24 when I do Remote Ip = 192.168.10.2 Wildecard ...
0
votes
1answer
21 views

4500X performance question

i have a pair of 4500x in VSS with 950x SVI and 6x BGP peers with no full tables (there is no other configs) now i want to configure 4-5x GRE tunnel and and 1-2x gre tunnel will have around 500mbps ...
0
votes
2answers
107 views

Connect 2 VLANs on Cisco SG300 with cable

I have a Cisco SG300 with 2 VLANs enabled, half the switch ports are on one VLAN, half is on the other. Both VLANs use the same subnet. I want traffic to travel between the 2 VLANs. I thought the 2 ...
0
votes
0answers
6 views

Cisco Topology Question [closed]

I have a 60x Rack with Junper ex4200 as top of rack for all racks and each rack should have 2x 10g lacp towards my access switch so i want to have 2x 4500x or 2x 6509 as core switch and 1x arista as ...
0
votes
1answer
29 views

Cisco ip helper-address

I am looking at the DHCP documentation and i cannot seam to find how to configure the router to use a loopback interface as the relay-agent. My objective is to use option 82 so that the dhcp server is ...
1
vote
1answer
50 views

How can I configure a Cisco router 4300 to allow internal server ip:80 to be accessed on public ip:4500

I have an internal web server on port 80. I need help commands maybe to configure port forwarding to access the server on my private network from a public IP Current running config interface ...
0
votes
1answer
569 views

How to enable RESTCONF server in IOS-XR?

I aim to enable RESTCONF server on Cisco IOS-XRv 9000. I did not find online anything about enabling HTTP server in this IOS-XR version. However, with NETCONF server can be enabled. For IOS-XE is ...
0
votes
3answers
34 views

L3 switch vlan routing to another gateway

I have a allied telesis switch with VLAN10 & VLAN 20 and a basic ISP Router with no VLAN configuration. ISP router IP is 172.30.50.253 PC1: 172.30.3.x/24 Gateway 172.30.3.254 VLAN30 interface ...
1
vote
2answers
2k views

Keep Cisco site-to-site tunnel up permanently

I have Cisco ASA site-to-site tunnel with remote and which i don't have control. I have following config: crypto ikev1 policy 10 authentication pre-share encryption aes hash sha group 2 ...
2
votes
2answers
2k views

How to keep an ASA tunnel up for lifetime?

We have a Cisco ASA and at the remote end I have no idea what the device is. This is what happening: When I send a packet or generate interesting traffic, it brings up the tunnel and everything ...
2
votes
8answers
39k views

How do I power on devices in CCNA Packet Tracer?

As the question says, i need an answer. I cannot find the power button.
0
votes
3answers
29 views

2 Routers, 2 Internet Connections, 2 Subnets - 1 Link?

I worked something out in my head, but I am having a hard time putting this into practice. We own 2 units, both within 100m of each other. Both units have internet connectivity, but there is a single ...
0
votes
1answer
80 views

Flapping MAC address issue on the uplink routed port [closed]

The scenario is like, in my VLAN 30 network, randomly one device stops communicating and when I check the Cisco L3 Stack switch, it shows the following error messages: Jul 27 13:59:55: %SW_MATM-4-...
0
votes
2answers
28 views

Per-VLAN DHCP pools on the switch

Let us say I have a switch on which I have created two VLANs 10 and 20. I have set ports 1-10 to be on VLAN 10 and ports 11-20 to be on VLAN 20. Presently the PCs in both VLANs are configured with ...
0
votes
2answers
34 views

Cisco IE4000 Blinking Amber Lights

I have an IE4000 Cisco Switch running my small air gapped network. I came in this morning and found that ALL the ports other than the Trunk port are blinking Amber. I checked the config and the ...
1
vote
0answers
22 views

How can I deny or block an IP Address in Cisco FTD

I have a Cisco Firepower Threat Defense firewall. I want to Block an IP and add blocked ip into BlockedIp rule. How can I achieve it via Web Interface or REST API ? Thank you!
1
vote
3answers
43 views

How to create/delete multiple VLANs in a single command?

If I want to create 3 VLANs, I've to do it one by one like this. conf t vlan 2 vlan 3 vlan 4 Same thing goes with deletion. conf t no vlan 2 no vlan 3 no vlan 4 Is there a way to do it in a single ...
0
votes
2answers
30 views

How to Balance SPAN Traffic from Redundant Switches

So we are wanting to deploy an IDS device to capture EAST-WEST traffic in a LAN. The actual topology is more complicated but our issue boils down to this: We are attempting to configure SPAN sessions ...
6
votes
2answers
707 views

Undo last command(s) in case of losing connection to a Cisco Router

I would like to configure an interface on a remote Cisco router (ISR 4000 series) with IPsec. The only way to connect to it is through the interface that I am trying to encrypt. I want to ensure that ...
1
vote
3answers
59 views

Policy Based Routing by Interface and IP

Is it possible on Juniper or Cisco to configure PBR where it matches on an ingress interface AND a source IP address? My scenario traffic flows are as follows: Router1 > Router2 > WAN_Optimiser &...
0
votes
0answers
18 views

test root-system password on IOS-XR

I've installed quite new NCS-5501-SE devices from Cisco. They're running well. I just remembered that then I initially deployed it, it asked me to set the root-system username and password, which is ...
0
votes
0answers
51 views

Untagged VLAN in EVPN+VxLAN

I am dealing with very strange issue but wanted to check with experts if i am doing anything stupid or not. I have small size EVPN+VxLAN clos network (OSFP+iBGP+Multicast+Arp-suppression (no ...
0
votes
0answers
12 views

Why does Cisco recommends NOT to use VLAN 1 as Management VLAN? [duplicate]

According to the following article; https://www.omnisecu.com/cisco-certified-network-associate-ccna/what-is-management-vlan-and-how-to-configure-management-vlan.php Cisco recommends NOT to use VLAN 1 ...
0
votes
0answers
19 views

L2TP/IPSec on Cisco ISR G2 issues

I am using several ISR G2 routers (819, 2901, etc) configured as L2TP/IPSec VPN concentrators. With current configuration it works good, but there are two odd things about it. I used standard ...
4
votes
3answers
268 views

How to remove switchport mode access from Cisco Switch 2960?

This is in Cisco Packet Tracer - this is not a real switch. Default interface config on Cisco Switch 2960 looks like this ! interface FastEthernet0/10 ! Then I put it in switchport mode access ! ...
1
vote
1answer
30 views

How to differentiate Layer 2 and Layer 3 Cisco Switch based on their config?

Layer 3 Cisco Switch can also been used as Layer 2 only. Is there any specific configuration in Cisco switch to verify this?
3
votes
1answer
144 views

BGP prefix filtering mismatch between peers

the peering between our router and the other peer already established, and we are trying to add new prefix route: 192.168.0.0/24 Failing command ip prefix-list PREFIX-FROM-A seq 15 permit 192.168.0.0/...
2
votes
4answers
77 views

Cisco N9K - Down an interface in response to another interface going down?

I currently have my transit providers plugged directly into my router. I really like this arrangement because when the ISP goes down this typically downs the interfaces which results in BGP peering ...
1
vote
1answer
33 views

Factory reset Cisco N520-4G4Z-A

I'm having some issues doing a factory reset on above mentioned Cisco box. I've tried several different key combinations and unfortunately previous owner does not remember password The examples on ...
1
vote
1answer
48 views

Cisco Packet Tracer Connection Error - The cable cannot be connected to that port

There are 3 NICs in the Router1 and 24 available ports in the Switch1. Is there any reason why I can't connect from Router1 to Switch1?
0
votes
2answers
45 views

n3k pause frame issue

We have 2x 10G (LACP) from our upstream that is connected to a n3k-c3064pq-10gx and on their switch they give us another 10g and we have monitor session from that 2x 10G (LACP) on this 10g port and ...
1
vote
0answers
21 views

Mistakenly added switch configuration on Cisco router 2951 so now it is showing gibberish data on CLI

I have Cisco 2951 router in which my colleague mistakenly uploaded switch configuration from tftp server. Now it is showing gibberish data on CLI when it boots up. I tried to get into the ROMmon mode ...
14
votes
3answers
44k views

How to Monitor Vlan Traffic?

We have migrated to a new ISP who provide us several services (Internet+VoIP+VoD) and have divided each service in one vlan 100,101,102 respectively. Now I'm looking for a solution to monitor each ...
2
votes
2answers
218 views

Can't add VLAN in the “allowed VLAN”

Why is this command not accepted? switchport trunk allowed vlan add 52,160,176,177,247 I tried adding only one VLAN; it's also not accepted. No error is shown or anything; it's just not showing when ...
0
votes
1answer
29 views

Cisco ASA 5506-X: clients periodically lose Internet access

Clients periodically lose Internet access, but I can connect to Cisco ASA and manage it. If i am ping sites, it works: Minsk# ping yandex.ru Type escape sequence to abort. Sending 5, 100-byte ICMP ...
2
votes
4answers
236 views

Difference between SVI and subinterface

Modern multi-layer switches seem to support both SVIs (switch virtual interfaces) and subinterfaces concepts. Both are virtual layer 3 concepts used to perform routing functions and some equipment ...
14
votes
4answers
12k views

How do you block bit torrent traffic with a Cisco ASA?

I have referenced an old external Cisco article on how to block Bit torrent traffic referenced on-line Here This procedure I have found only works 50% of the time. I find blocking bit torrent ...
1
vote
1answer
22 views

GNS3 can not ping from ethernet interface to serial interface

So I am doing a Lab for one of my classes involving ipv6 and routing using EIGRP. When I set-up the network and assign the router interfaces with IPV6 address I get an issue pinging the whole network. ...
0
votes
1answer
59 views

Duplicated Vlan ID

I have one flat network with our data center and it is causing as a lot of issues, so i had to design a new network to separate the buildings from the data center, when I designed the new network i ...
0
votes
1answer
76 views

Capturing dot1q packets with Wireshark on a PC

I have spent the last few hours trying to capture some trunk packets so I can see and examine the dot1q VLAN field. I have tried mirroring the trunk port to my PC using the following commands on Cisco ...

1
2 3 4 5
69